fix: FPE: introduce std::abs for stepSize check in EigenStepper (#698)

An FPE occurrence was [reported in Athena](https://its.cern.ch/jira/browse/ATLASRECTS-5989) when running the Iterative Vertex Finder, which should be fixed with this PR.
acts-project · Feb 5, 2021 · b0987df · b0987df
1 parent 4d7f1d7
commit b0987df
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/Core/include/Acts/Propagator/EigenStepper.ipp b/Core/include/Acts/Propagator/EigenStepper.ipp
@@ -166,8 +166,8 @@ Acts::Result<double> Acts::EigenStepper<B, E, A>::step(
 
     // If step size becomes too small the particle remains at the initial
     // place
-    if (state.stepping.stepSize * state.stepping.stepSize <
-        state.options.stepSizeCutOff * state.options.stepSizeCutOff) {
+    if (std::abs(state.stepping.stepSize) <
+        std::abs(state.options.stepSizeCutOff)) {
       // Not moving due to too low momentum needs an aborter
       return EigenStepperError::StepSizeStalled;
     }